1. Field of the Invention
This invention relates to pipe coupling apparatus, and more particularly to a pipe coupling apparatus having a coupling case for surrounding an outer periphery of an existing pipe in a sealed state, the coupling case defining a pipe coupling opening for coupling a new pipe, and an executing opening formed in the coupling case for cutting a branching opening in the existing pipe. A sealing device is mounted on the coupling case for sealing the executing opening. The branching opening is cut while a fluid is prevented from flowing out of the executing opening.
2. Description of the Prior Art
The above pipe coupling apparatus allows the new pipe to be connected to the existing pipe through the coupling case without requiring a separate operation to stop the fluid flowing through the existing pipe. The existing pipe and new pipe may be connected to be in intercommunicating condition by attaching the coupling case to the existing pipe, coupling the new pipe to the coupling opening of the coupling case, cutting the branching opening in the existing pipe, and sealing the executing opening with the sealing device. It is necessary to carry out the operation in the sequence that, after attaching the coupling case to the existing pipe, the new pipe is connected to the coupling opening and laid along a predetermined course, and thereafter the branching opening is cut in the existing pipe.
After the existing pipe and new pipe are connected through the coupling case, a fluid line may be switched, without stopping the fluid flow as noted above, to cause the fluid to flow from one of passages defined by the existing pipe and communicating with the branching opening to the new pipe. The portion of the existing pipe defining the other passage may be removed. In this case, the portion of the existing pipe to be put out of service must be cut and removed after shutting the other passage with a valve introduced into the coupling case through the executing opening and into the existing pipe through the branching opening.
According to the prior art noted above, the existing pipe and new pipe are connected through the coupling case without stopping the fluid flow. The fluid line may be switched, again without stopping the fluid flow, to cause the fluid to flow from one of the passages defined by the existing pipe and communicating with the branching opening to the new pipe. The portion of the existing pipe defining the other passage may be removed. For this purpose, the new pipe is laid in place after completing attachment of the coupling case to the existing pipe. After the new pipe is laid in place, the branching opening is cut in the existing pipe, and the valve is introduced into the coupling case through the executing opening. Next, the other passage defined by the pipe and communicating with the coupling opening is shut with the valve, and the portion of the pipe to be put out of service is cut and removed. Such a process is incapable of consecutively and efficiently carrying out the operations relating to the coupling case to attach the coupling case to the existing pipe, to cut the branching opening in the existing pipe, and to introduce the valve into the coupling case through the executing opening, as well as the pipe installing operation relating to the new pipe and existing pipe.